Circular economy not 'silver bullet' for resource crunch
Industrial systems based on circular economy models will be constrained by end-of-life material availability, limiting future improvements in process efficiency, scientists claim.
A wider materials efficiency framework is required, they argue, one which encompasses not just circular resource flow systems but mitigation options for industrial carbon emissions and consumer demand.
This central message was one of the key conclusions drawn from several academic papers in the Philosophical Transactions of the Royal Society A journal, which collectively looked to examine how greater resource efficiency could be achieved in practice.
According to the findings, demand for material extraction and processing is likely to double in the next 40 years. As industry drives nearly one-third of global energy demand, it warns that using less materials in manufacture will become critical to cut this level of demand and reduce emissions.
"For some materials, this goal can be achieved by increasing recycling, which is the primary goal of discussions around the phrase 'circular economy', although this is constrained by the availability of scape of end-of-life material, and many practical difficulties associated with collection, sorting and separation," the document states.
As energy-intensive sectors such as steel, aluminium, cement, plastics and paper are already among the most energy-efficient, there is a finite amount they can improve, so lowering demand for these types of materials will need to be built into societal expectations.
This would mean constructing new buildings with less cement, manufacturing cars with less steel and designing gadgets with less plastic. According to one scientist, in the UK alone demand for new steel needs to reduce to 30% of current levels in order to meet emission targets.
The paper goes on to identify six technical options for driving greater material efficiency: lightweight design; reducing yield losses; diverting manufacturing scrap; reusing components; longer-life products; and more intense use.
However it acknowledges that the six strategies "may conflict with each other" and that these conflicts need further investigation.
For example, lightweighting could inhibit the potential for reuse unless the architecture in which components are housed are standardised. Reducing material yield losses meanwhile cuts down on the amount of waste available for recovery, and could hinder supply and demand for secondary production material flows.
Challenges around sustainable consumption also need to be addressed, most notably the concept of happiness and wellbeing in a less material hungry society.
"We are short of visions in a technologically advanced future with reduced consumption," the document points out, adding that the 'paperless office' has yet to emerge and that there is no data yet to support the concept that e-readers and other portable devices reduce total environmental impacts.
Foremost, a pressing case is made for incorporating material efficiency as an element of wider industrial emissions abatement strategies - essential if carbon reduction targets are to be achieved.
"Sufficient technical options exist to deliver current levels of material service with significantly less material, many of which could be implemented immediately if so demanded by customers, and some of which could be made cheaper by technical innovations," the document concludes.